The Worldwide Interoperability for Microwave Access, (a.k.a., WiMAX) is a telecommunications technology aimed at exchanging wireless data. WiMAX specified standards include point-to-point links and full mobile cellular type access. WiMAX is based on the IEEE 802.16 set of standards. To promote conformance and interoperability of WiMAX equipment and software, various stakeholders formed the WiMAX forum. The WiMAX forum publishes several technical documents that specify aspects of a WiMAX system.
WiMAX forum technical documents include the WiMAX Forum Network Architecture. The WiMAX Forum Network Architecture specification includes documentation for such things as definitions, Architecture Tenets, a Reference Model, and Reference Points. The WiMAX Forum Network Architecture Release 1.1.0, Jul. 11, 2007 available from the WiMAX forum at www.wimaxforum.org is hereby incorporated herein by reference.
The system architecture promulgated by the WiMAX forum defines various entities that include Mobile Stations (MSs), Base Stations (BSs), Access Service Networks (ASNs), Access Service Network Gateways (ASN-GWs), and Connectivity Service Networks (CSNs). Also included in the WiMAX Forum Network Architecture are protocols to handoff a moving device from one BS to another and from one ASN or ASN-GW to another.
Overview
A method of operating a communication system is disclosed. A first communication session between a first base station and a mobile station is established. A service session between a first access network and the mobile station is established. When the mobile station moves to the service area of a new base station, a second communication session between a second base station and the mobile station is established. A distance between the first base station and the second base station is determined. If the distance exceeds a criteria, the service session is handed off to a second access network. The criteria, which must be greater than zero, corresponds to a number of base station service areas separating the first base station and the second base station.
A communication system is disclosed. A first access network is coupled to a first base station and a second base station. A number of base station service areas separate the first base station and the second base station. A second access network is also coupled to the first base station and the second base station. The first base station establishes a communication session with a mobile station. The first base station establishes a service session between the mobile station and the first access network. The second base station establishes a service session between the mobile station and the second access network if a distance between the first base station and the second base station satisfies a distance criteria. The distance criteria, which must be greater than zero, is based on a number of base station service areas separating the first base station and the second base station.
A first communication session is established between a first base station and a mobile station. A service session is established between a first Access Service Network Gateway (ASN-GW) and the mobile station. A second communication session is established between a second base station and the mobile station. A distance between the first base station and the second base station is determined. If the distance exceeds a criteria, the service session is handed off from the first ASN-GW to the second ASN-GW. The criteria, which must be greater than zero, corresponds to a number of base station service areas separating the first base station and the second base station.